People who receive the Johnson & Johnson COVID-19 vaccine are at elevated risk of getting a severe autoimmune disorder that can cause paralysis, according to a new study. Researchers used data from the Vaccine Safety Datalink, which is run by the Centers for Disease Control and Prevention (CDC). They found (pdf) 21 potential cases, 11 of which were confirmed, of Guillain-Barré syndrome (GBS) in people who got the shot. Most happened with 13 days of vaccination. The incidence rate of confirmed cases per 100,000 person-years was 34.6 during the 1 to 21 days after administration, much higher than the historical background rate of 2 per 100,000 person-years. Adjusted rates also came in higher than the expected and background rates. Researchers determined the incidence of GBS was much lower among those who got a messenger-RNA-based vaccine, or a Moderna or Pfizer shot. The rates after those vaccines were similar to background rates. The …